bikeshed/src/com/google/gwt/sample/expenses/gwt/client/Scaffold.java

/*
 * Copyright 2010 Google Inc.
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * 
 * http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.google.gwt.sample.expenses.gwt.client;

import com.google.gwt.app.place.Activity;
import com.google.gwt.app.place.ActivityManager;
import com.google.gwt.app.place.ActivityMapper;
import com.google.gwt.app.place.CachingActivityMapper;
import com.google.gwt.app.place.FilteredActivityMapper;
import com.google.gwt.app.place.IsWidget;
import com.google.gwt.app.place.PlaceController;
import com.google.gwt.app.place.PlaceHistoryHandler;
import com.google.gwt.app.place.ProxyListPlace;
import com.google.gwt.core.client.EntryPoint;
import com.google.gwt.core.client.GWT;
import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.Element;
import com.google.gwt.event.shared.EventBus;
import com.google.gwt.requestfactory.client.AuthenticationFailureHandler;
import com.google.gwt.requestfactory.client.LoginWidget;
import com.google.gwt.requestfactory.shared.Receiver;
import com.google.gwt.requestfactory.shared.RequestEvent;
import com.google.gwt.requestfactory.shared.UserInformationRecord;
import com.google.gwt.requestfactory.shared.RequestEvent.State;
import com.google.gwt.sample.expenses.gwt.request.ExpensesEntityTypesProcessor;
import com.google.gwt.sample.expenses.gwt.request.ExpensesRequestFactory;
import com.google.gwt.user.client.Window.Location;
import com.google.gwt.user.client.ui.HasConstrainedValue;
import com.google.gwt.user.client.ui.RootLayoutPanel;
import com.google.gwt.valuestore.shared.Record;
import com.google.gwt.valuestore.shared.SyncResult;

import java.util.HashSet;
import java.util.Set;

/**
 * Application for browsing the entities of the Expenses app.
 */
public class Scaffold implements EntryPoint {
  public void onModuleLoad() {
    ScaffoldFactory factory = GWT.create(ScaffoldFactory.class);

    /* App controllers and services */

    final EventBus eventBus = factory.getEventBus();
    final ExpensesRequestFactory requestFactory = factory.getRequestFactory();
    final PlaceController placeController = factory.getPlaceController();

    /* Top level UI */

    final ScaffoldShell shell = factory.getShell();

    /* Display loading notifications when we touch the network. */

    eventBus.addHandler(RequestEvent.TYPE, new RequestEvent.Handler() {
      // Only show loading status if a request isn't serviced in 250ms.
      private static final int LOADING_TIMEOUT = 250;

      public void onRequestEvent(RequestEvent requestEvent) {
        if (requestEvent.getState() == State.SENT) {
          shell.getMole().showDelayed(LOADING_TIMEOUT);
        } else {
          shell.getMole().hide();
        }
      }
    });

    /* Check for Authentication failures or mismatches */

    eventBus.addHandler(RequestEvent.TYPE, new AuthenticationFailureHandler());

    /* Add a login widget to the page */

    final LoginWidget login = shell.getLoginWidget();
    Receiver<UserInformationRecord> receiver = new Receiver<UserInformationRecord>() {
      public void onSuccess(UserInformationRecord userInformationRecord,
          Set<SyncResult> syncResults) {
        login.setUserInformation(userInformationRecord);
      }
    };
    requestFactory.userInformationRequest().getCurrentUserInformation(
        Location.getHref()).fire(receiver);

    /* Left side lets us pick from all the types of entities */

    HasConstrainedValue<ProxyListPlace> listPlacePickerView = shell.getPlacesBox();
    listPlacePickerView.setAcceptableValues(getTopPlaces());
    factory.getListPlacePicker().register(eventBus, listPlacePickerView);

    /*
     * Top of the screen is the master list of a master / detail UI. Set it up
     * to filter ProxyPlace instances to an appropriate ProxyListPlace, and put
     * a cache on it to keep the same activity instance running rather than
     * building a new one on each detail change.
     */

    CachingActivityMapper cached = new CachingActivityMapper(
        new ExpensesMasterActivities(requestFactory, placeController));
    ActivityMapper masterActivityMap = new FilteredActivityMapper(
        factory.getProxyPlaceToListPlace(), cached);
    final ActivityManager masterActivityManager = new ActivityManager(
        masterActivityMap, eventBus);

    masterActivityManager.setDisplay(new Activity.Display() {
      public void showActivityWidget(IsWidget widget) {
        shell.getMasterPanel().setWidget(
            widget == null ? null : widget.asWidget());
      }
    });

    /* Bottom of the screen shows the details of a master / detail UI */

    final ActivityManager detailsActivityManager = new ActivityManager(
        new ExpensesDetailsActivities(requestFactory, placeController),
        eventBus);

    detailsActivityManager.setDisplay(new Activity.Display() {
      public void showActivityWidget(IsWidget widget) {
        shell.getDetailsPanel().setWidget(
            widget == null ? null : widget.asWidget());
      }
    });

    /* Hide the loading message */

    Element loading = Document.get().getElementById("loading");
    loading.getParentElement().removeChild(loading);

    /* Browser history integration */
    PlaceHistoryHandler placeHistoryHandler = factory.getPlaceHistoryHandler();
    placeHistoryHandler.register(placeController, eventBus, 
        /* defaultPlace */ getTopPlaces().iterator().next());
    placeHistoryHandler.handleCurrentHistory();

    /* And show the user the shell */

    RootLayoutPanel.get().add(shell);
  }

  // TODO(rjrjr) No reason to make the place objects in advance, just make
  // it list the class objects themselves. Needs to be sorted by rendered name,
  // too
  private Set<ProxyListPlace> getTopPlaces() {
    Set<Class<? extends Record>> types = ExpensesEntityTypesProcessor.getAll();
    Set<ProxyListPlace> rtn = new HashSet<ProxyListPlace>(types.size());

    for (Class<? extends Record> type : types) {
      rtn.add(new ProxyListPlace(type));
    }

    return rtn;
  }
}